Powder burn temp?

[daved20319]

Possibly a silly question, but does powder burn speed equate to burn temperature as well? And if not, is there a temperature chart out there like the burn rate chart? Just put a new barrel on my Creedmoor, and I'd like to make it last as long as possible. I tend to shoot mid-range loads, so that helps, but if I can get acceptable performance from a cooler burning powder as well, that works for me . And no, I'm not expecting a huge difference in barrel wear, but I'll take any reduction I can get, as long as it doesn't impact accuracy. Later.

Dave

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[osprey]

My gut feeling is faster powders do burn hotter and generally would follow burn rate chart. I don't think you really need to worry about it too much in a bolt gun in 6.5 CM. If it is a semi auto then maybe if you are into sustained strings of fire. I would probably just use the powder that provides the best accuracy and not let the barrel get too hot bolt or gas gun.

 

[oremike]

Some powder manufacturers state the " this is a cooler burning powder and will prolong barrel life" W-748 is one:

Winchester – Hodgdon Powder Company

winchesterpowder.com

 

[74bronco]

here ya go, from cold to hot

 

[DizzyJ]

My gut feeling is faster powders do burn hotter and generally would follow burn rate chart. I don't think you really need to worry about it too much in a bolt gun in 6.5 CM. If it is a semi auto then maybe if you are into sustained strings of fire. I would probably just use the powder that provides the best accuracy and not let the barrel get too hot bolt or gas gun.

This would be my thought as well concerning heat. Though I have no way to prove this.

 

[Quirt Evans]

What's interesting about that burn/temp chart, is if the 4>5 at both the high and low ends are tossed, the vast majority of the powders are all within ~250>300 degrees or so.
As a percentage of temp, their really isn't all that much difference.

 

[Knute]

I know there's some smart chemist guy out there that will pounce on this but I do not believe smokeless powder burn temps have much if anything to do with barrel wear.

Modern powders "propel" bullets by the burned propellant's gas pressure, and not heat.

Barrels wear from bullets impacting the lands only, I think...

 

[74bronco]

throat erosion is very effected by powder burn temp, case capacity vrs bullet diameter, i.e the larger the case and smaller the bullet dia. the worse, example 308 vs 243, the 243 suffers much worse throat erosion.

shoulder angle and neck length effect it as well along with the quality of steel in the barrel.
you will burn up a 243 barrel in 1200-1400 rds using a hot powder like vit 540n but use h1000 and you might get 1800-2000 rds

then change the shoulder angle from 20° to 30° and lengthen the neck, something like the 6mm slr or 6 creed and with a cooler powder we've seen barrels stay competitive to 3000 plus rds.

draw 2 lines from the shoulder angle , following the angle towards the bullet and out the neck, if they intersect outside of the case neck you will get more throat erosion then if it stays within the brass's neck, they say that that intersection is the hottest point of combustion when a bottleneck cartridge is fired.

fact or fiction you choose

 

[thorborg]

The sand blast effect of unburnt powders plays a significant role in barrel "erosion".

 

[osprey]

In the refrigeration world pressure directly correlates with temperature and higher pressure would mean higher temperature. I always thought barrel erosion had much to do with the velocity of the gasses. A high volume of gas having to escape a smaller bore would naturally have higher gas velocity and higher potential erosion vs the same volume of gas escaping a larger bore. Could be wrong though as I haven't stayed at a holiday inn lately.

 

[DizzyJ]

RELOADERS CORNER: Barrel Throat Erosion

How long does a barrel last? About 5 seconds. KEEP READING Glen Zediker As is by now common enough in this column I write, ideas for topics very often come from questions that are emailed to me. As…

www.mssblog.com

 

[DizzyJ]

https://apps.dtic.mil/dtic/tr/fulltext/u2/a017828.pdf

 

[DizzyJ]

 

[Quirt Evans]

Some good points made in the above video, as well as in other posts.
We do know that massive charge weights of powder in small bores, (think of a Weatherby .30-.378,) have huge amounts of "jet effect", which impacts bore erosion.
And large bores, (like a .458 Win Mag,) are also operating at high pressures, but exhibit much less erosion because the expansion ratio is so much larger,, so the jet effect is much reduced.
Now for a comparison; Black powder is lower pressure, but has a very quick pressure spike, (black doesn't burn as much as it explodes,) and it heats-up barrels fast,, this is due to the actual flame of the burn which is long lasting compared to smokeless.
Fire 5>6 rounds of black powder shotgun shells as fast as you can and the barrel will sear your flesh, while the same shots with smokeless will not heat-up the barrel nearly as much.
Erosion is not any one thing, but combinations of heat/pressure/gas velocity, and the ratios of each can vary.